CR-39 In Semi-Rimless Frames

[Wondering Optician]

CR-39 in semi rimless frames?????? What do you think? for the last several years I have not put a single CR-39 lens in to a semi rimless frame because of the issues with chipping and the cosmetic effect that cause ... I seem to have the issue with giving something to my patient that I know will have a relatively high chance of chipping over the lifetime of the glasses.. I treat every one of my patients like they are family and I don't want that stigma of there lenses chipping to be associated with the product that I had sold them... in other words i don't want them to think that my product is defective because every time they want to save a buck and put CR-39 lenses into a semi rimless frame it chips ... i would like to know what everyone thinks on this subject??? is it just me being stupid about this or is this a valid point? :hammer:


thanks..

The Wondering Optician.....

[iiiiisoptom]

Likewise, we would not put cr39 into a nylon frame, where there is a viable alternative (and in virtually all cases there is).
If you explain to the patient that a "chip resistant" material is required for a nylon frame, they will almost always go with it.
We would prefer to use 1.53 (Trivex), 1.6, and occasionally 1.67 & 1.7
You MIGHT get away with using cr39 in a moderate minus lens, but far less likely in plus, especially if the frame is relatively stiff. I don't think it's worth the risk, and there is not too much difference in price to the patient to get Trivex over cr39. We would rather change the frame to a full rim, if the patient were to "insist" on cr39, and in most cases would rather lose the sale all together. We warn the patient that the cr39 lens will be much more likely to chip in the nylon frame than Trivex. We haven't had a single Trivex lens return to us with a chip, but in the past we had plenty of cr39 come back.

[Wondering Optician]

Likewise, we would not put cr39 into a nylon frame, where there is a viable alternative (and in virtually all cases there is).
If you explain to the patient that a "chip resistant" material is required for a nylon frame, they will almost always go with it.
We would prefer to use 1.53 (Trivex), 1.6, and occasionally 1.67 & 1.7
You MIGHT get away with using cr39 in a moderate minus lens, but far less likely in plus, especially if the frame is relatively stiff. I don't think it's worth the risk, and there is not too much difference in price to the patient to get Trivex over cr39. We would rather change the frame to a full rim, if the patient were to "insist" on cr39, and in most cases would rather lose the sale all together. We warn the patient that the cr39 lens will be much more likely to chip in the nylon frame than Trivex. We haven't had a single Trivex lens return to us with a chip, but in the past we had plenty of cr39 come back.

... thank you for your help....

[Chris Ryser]

There was a time when CR39 became popular in the late 1970s.....................prior to that there was nothing else than glass.

There were lots of different frame designs in rimless frame from the Numont to the Balgrip in the 1950s then the Amor frames from Lissac followed in the late 50s by the first totally successful NYLOR by Essel=now Essilor. This was probably the most popular of all.

It was all mounted in glass by the millions and millions for the first 75 years of last century. When CR39 came in it was advertised as the unbreakable plastic. Glass and CR39 are optically still the best lenses.

So I do not understand the concern you young people have:

CR-39 in semi rimless frames?????? What do you think? for the last several years I have not put a single CR-39 lens in to a semi rimless frame because of the issues with chipping and the cosmetic effect that cause ...

We used to mount these frames and lenses without them chipping unless they were abused by the consumer............(when I woke up in the morning the lens was chipped on the night table} which still is used a hundred years later.

[cocoisland58]

I agree with Chris. What do you think we used for years and years? My first pair of drilled rimless were CR39 and never chipped. CR39 would not be my material of choice for rimless but I'll still use it if someone does not want to pop for the extra charge to upgrade to poly. I just note on their record that they declined it and go ahead with the order. If the lens has enough of an edge they will be fine. Poly chips and flakes too you know.

[David Kincade]

Some of the modern frames use a metal ridge instead of plastic figure 8 liner to secure the groove. This was not used when we had only glass and CR-39. That metal ridge increases the chance of chipping to almost 100% in CR-39 (OK, it's not that high, but ti seems like it when I get the parade of p*****-off patients through my offices). We use Trivex, etc.

[KStraker]

Some of the modern frames use a metal ridge instead of plastic figure 8 liner to secure the groove. This was not used when we had only glass and CR-39. That metal ridge increases the chance of chipping to almost 100% in CR-39 (OK, it's not that high, but ti seems like it when I get the parade of p*****-off patients through my offices). We use Trivex, etc.

Which makes the lens thinner and thus more prone to chipping, IMO. I have no problems what so ever with cr39 chipping any more than any other material.

[chip anderson]

I'm O.K with CR 39 rimless. But one should know the wearer. Some folks would wear CR-39 for six years and have the glasses look pristine, other could destroy them one way or another in six weeks.

Chip

[Fezz]

I'm OK with a Leatherman multi-tool, but my fully stocked tool chest is much better.

I'm OK with a length of 15lb test fishing line and an empty beer can for fishing, but my rod and reel works much better.

I'm OK with a with Grandpa's old bow saw, but my trusty Dolmar/Makita chainsaw is much better.

I'm OK with WD-40 for loosening a rusty bolt, but Kroil works much better.

I'm Ok with my Lee Loader, but my RCBS RockCrusher works much better.

I'm Ok with a can of Old Milwaukee, but a bottle of Chimay is much better.

I'm OK with with trekking to work on my old Schwinn(sp?) bicycle with the bananna seat and tassles out the grips, but my Cowboy Cadillac is much better.

I'm Ok with my old Crossman slingshot, but my S&W 629 44 Magnum topped with a 2x scope is much better.


I'm OK with Cr-39.......................................just not in rimless. It really is not better.


;):cheers::cheers::cheers::cheers::D

[DragonLensmanWV]

We still use CR-39 is some grooved rimless, (heck I did an Art-Craft Orbal in CR-39 last week) and the only chipping we see is when the customer drops them or steps on them or somesuch.As for the metal tops without the nylon figure-8 liner, we have our edger make a wider groove so the edge of the lens can sit squarely against the flat part of the rim and the metal ridge is not acting as a splitting wedge.

Of course in the early drill mount days, all you had was CR-39. And facets! People could somehow bend their frame completely out and as soon as you touched a plier to them, the lens broke. How they could bend them so far without breaking was a mystery. You quickly learned to remove the lenses,straighten the frame, then remount the lenses.

[Now I See]

I don't mind using CR39, here's what I like to make sure of FIRST, though..

1. The pt is fully aware that they must treat their specs like jewelry, due to the fact that they will chip if mistreated.

2. I like to have about 2mm of thickness for CR39...I've done it with 1.8mm, but I was sweating (and talking to the lens :hammer:) the whole time. :D

3. I have had trouble with the metal ridge in the top (the ones that David Kincade mentioned) so I like to use a "less chippable" material **(I do not think that "chippable" is a real word, but you get my point :D)**

[Now I See]

....As for the metal tops without the nylon figure-8 liner, we have our edger make a wider groove so the edge of the lens can sit squarely against the flat part of the rim and the metal ridge is not acting as a splitting wedge.

Thanks for the tip! :cheers:

Of course in the early drill mount days, all you had was CR-39. And facets! People could somehow bend their frame completely out and as soon as you touched a plier to them, the lens broke. How they could bend them so far without breaking was a mystery. You quickly learned to remove the lenses,straighten the frame, then remount the lenses.

LOL! That is one of those lessons that you learn one time and NEVER forget! Heck, I could probably remember the date and time and patient that it happened to! :shiner::idea:

[71pagoda]

Thing about how much you are saving vs a satisfied customer. Under $10.00 per pair sv.

[obxeyeguy]

Which makes the lens thinner and thus more prone to chipping, IMO. I have no problems what so ever with cr39 chipping any more than any other material.

I'm with KStraker on this. I have no problem, other than abuse, with CR-39. With the added expense of trivex, you can almost buy a replacement pair of plastic.:bbg:

[Uilleann]

Poly generally works best for us with grooves - from a strictly material standpoint. I would possibly use 1.60, or as a last resort on a higher Rx a 1.67. I would caution against trusting that the glasses will see no abuse - no matter how careful the patient may tend to be. It only takes one accident or slight frame bend to cause a very unhappy situation for both ECP and patient. While it is certainly true that no material is 100% guaranteed against breaking, chipping or cracking, there are good choices and bad.

If you are not taking the time to educate every patient on what lens is most appropriate for their Rx first, and then most appropriate for their frame second, I might kindly suggest that you may want to re-visit the dispensing process in your office. YOU are the professional - and it is YOUR knowledge and expertise that separates you from everyone else. It is our position to make sure that a pt. with a low Rx, or a plus Rx is not the best candidate for semi-rimless groove frame styles. Ensuring your frame selection is well rounded and not overloaded with semi-rimless (a serious problem in two of my past practices) is also helpful.

There is always a best possible solution for a patient in your dispensary. We design around the Rx and lens first, the frame (comfort, fit, cosmetics and appropriate design for the RX) secondly, and value for our patient third. Our doctors and staff believe in this approach, and it works very well for our patients. Our breakage rate has dropped by over 3/4 what it was a year and a half ago, and our patients feedback has been extremely positive.

Best of luck in your case. May your patient enjoy the best pair of eye wear they've ever had in their life - and may YOU make them! :cheers:

Brian~

[Chris Ryser]

Whatever works for most the best is the more expensive version, but with good craftmanship, any material could be properly fitted so that there is no other problems than patient abuse.

[Fezz]

Whatever works for most the best is the more expensive version, but with good craftmanship, any material could be properly fitted so that there is no other problems than patient abuse.

I want to believe you here Chris, but I can not. I have seen too many problems over the years to believe that any material, with or without great craftsmanship, can be used. Sure, sure, I know that even glass lenses can be used! I have done it many times. But, I know that there are more problems with using some materials, than patient abuse.

[Crazy-bout-Optics]

Yes, I would gladly use CR39 in a semi-rimless when:

1) Pts start taking care of their glasses and stop abusing them

2) I could have the lenses made by someone who knows what they are doing (I work in LC land)

The first could take place, slowly, over time through education. The second I have no control over since I am in a corporate environment. So until that changes I just tell the Pt "With this frame and lenses with SC, UV, with A/R etc your total is $XX.xx" I do not really find it necessary to get into the specifics of lens material with the Pt unless the pt does not want what I have offered to them. I do explain why I recommend the options that I do. Some are fine, if there is any objection and they want the cheapest, and thats CR39, then I tell them we have to change the frame and explain why.


As I side note I have had Pts from Mexico that had drilled CR39 that looked awesome, even though I could tell it was a higher minus Rx and they had them for about 4 years. Maybe people there treat their glasses better? :)

My 2 cents for the day. This is a great thread that got me thinking, as before I read the responses I initially thought "No way"


~Crazy

[Uilleann]

This is indeed a good thread - both for ECP's as well as the general public. There is no doubt that there is a large segment of the glasses wearing community who take impeccable care of their eye wear. And to all of them I say Bravo! Your neighborhood optician thanks you from the bottom of our heart! :) Yet, no amount of diligence, care and prevention can protect 100% against the "chance accident" that can and likely will chip or break a given lens material in a grooved semi-rimless frame.

Educate as best you can, direct patients to proper lens/frame marriages based on the best visual solution for their vision and lifestyle needs, and use your knowledge and skill to make them look great while not draining the coffers...and you're all set! Simple! :bbg::D

[For-Life]

There was a time when CR39 became popular in the late 1970s.....................prior to that there was nothing else than glass.

There were lots of different frame designs in rimless frame from the Numont to the Balgrip in the 1950s then the Amor frames from Lissac followed in the late 50s by the first totally successful NYLOR by Essel=now Essilor. This was probably the most popular of all.

It was all mounted in glass by the millions and millions for the first 75 years of last century. When CR39 came in it was advertised as the unbreakable plastic. Glass and CR39 are optically still the best lenses.

So I do not understand the concern you young people have:



We used to mount these frames and lenses without them chipping unless they were abused by the consumer............(when I woke up in the morning the lens was chipped on the night table} which still is used a hundred years later.

My father used to always tell me the stories about how these frames and glass lenses used to keep the store doors open, because they constantly broke.

[AdmiralKnight]

Wow, I really feel like I'm in the minority here... I generally don't let the frame determine what material I use, unless it's absolutely necessary. Nylon, Zyl, Full metal, whatever (not including drillmounts). If the Rx doesn't call for more than CR-39, I don't bother. I find that generally, if you can get a 2.3-2.5mm edge thickness on a nylon, you shouldn't have any issues with chipping (other than patient abuse, obviously), which from my experiance we can usually get from anything around a -1.00 in a stock lens, and can easily be surfaced in any other power. This doesn't count for those damned metal T-Bar frames. Who ever thought THAT would be a good design idea? We try to make sure none of those get into our office, and if one slips by, it's gone asap.

[Jubilee]

I will recommend an impact resistant material. I explain to the patient that with Cr39, all it takes is to drop your glasses and have them hit the edge, and you can see chipping. Besides, most who lean towards the semi-rimless seem to want "lighter" glasses anyway, so Trivex or poly would also help in that endeavor.

IF they decide to keep with Cr39, I simply notate it on the file, and if there is any future issues, I can at least know they were warned.

Cassandra

[iiiiisoptom]

Ask yourself, if you were going to dispense lenses for yourself into a semi-rimless frame, what material would you choose? If it's good enough for you to have Trivex, or poly or 1.6, why not for the patient?
We used to have a dispenser who wore a sem-rimless frame with cr39 lenses, but she was very meticulous in everything she did, so there is no way she would have chipped them, but we can't assume that all, or even some, of our patients are going to be as careful.

[obxeyeguy]

I explain to the patient that with Cr39, all it takes is to drop your glasses and have them hit the edge, and you can see chipping.

Better hope that those -1.25's in poly don't chip after dropping, as you are implying that they won't.

This cracks me up with the use of over-kill products like 1.60, poly, trivex for even the simplist of scripts. What next?? The little old lady with a walker, and selling her liberty sports specs because she most likely will take a header??

Eyewear should'nt be bounced off the concrete period. Yes, the plastic MAY chip, as any of them can, but they all will scratch...

[FullCircle]

I have no problem running Cr-39 in a rimless (except the aforementioned metal t-bar), I just remind the girls out front that they should advise the customers about the increased likelyhood of the lenses chipping and that they (the retail staff) should put a note in the file that the conversation took place.

But, then I too remember the facets and drill jobs that were in plastic. And grooving those plus lenses on a Santinelli groover. I hated that thing.

The second I have no control over since I am in a corporate environment. So until that changes I just tell the Pt "With this frame and lenses with SC, UV, with A/R etc your total is $XX.xx" I do not really find it necessary to get into the specifics of lens material with the Pt unless the pt does not want what I have offered to them

I'm sorry, I beg to differ. You do have control. You have the same obligations to your customer/patient as an optician at a private office. You are supposed to be the knowledgeable one and explain to the person why that +5 in a grooved rimless isn't the best choice. Then you CYA and put a note in the file when they still want plastic. You've done your job, the customer is on the same page as you, the lab isn't griping and questioning your sanity :bbg:, and all is right in the world for a moment.